worm-eaten
蠧 centers on the idea of being eaten away by worms or insects, describing something worm-eaten or damaged by boring pests.
蠧 combines 虫 (insect) with a phonetic component derived from 橐, suggesting an insect that bores into and eats away material. The modern form is complex and its exact historical development is uncertain.
The bottom is 虫 (insect), and the upper part looks like a container (士 over 冖) with a stone (石) inside. Imagine a stone box full of worms eating through everything until it's worm-eaten.
For ト, picture a toe being nibbled by a worm: toe -> ト, and the worm-eaten toe matches the kanji's meaning.
insect damage (to crops, clothing, etc.)